The present invention disclosed herein relates to non-volatile memory devices and methods of manufacturing the same, and more particularly, to non-volatile memory devices having a data storage layer that is formed of an organic layer and methods of manufacturing the non-volatile memory device.
Typical inorganic memory devices intrinsically have insufficient flexibility and must be processed in a relatively high temperature range. In contrast, since organic memory devices have a potential capable of manufacturing a flexible lightweight plastic memory module at a lower temperature and a lower cost, a great deal of research into the organic memory devices has been conducted. Among various types of the organic memory devices, recent studies have been related to non-volatile memory devices including an organic-resistive-switching diode memory and an organic field-effect transistor (OFET) memory. The organic-resistive-switching diode memory devices may comprise an organic-resistive layer between two electrodes and may generally operate as one of an electrically insulating material or an electrically conductive material under appropriate voltage conditions. However, since the organic-resistive-switching diode memory devices do not have a third electrode addressing a signal, transistors addressing signals in two-dimensional memory arrays are required. Alternatively, since the OFET memory devices have three electrodes in unit transistors, the OFET memory devices may address signals alone.
The OFET memory devices may be categorized into two types according to a memory effect. The first type is a ferroelectric OFET memory device and the second type is a charge-storage OFET memory device. Functionality of the ferroelectric OFET memory devices is generated from ferroelectric gate dielectric layers that are polarized under a predetermined electric field (gate voltage), and accordingly, a research objective is to maintain a polarized state in a continuous (repetitive) reading operation. With respect to the charge-storage OFET memory device, the gate dielectric layers having functional groups may be charged to control a gate voltage. In order to facilitate switching, an additional dielectric layer may be inserted between the gate dielectric layer and an organic semiconductor layer. However, it is not good to use double dielectric layers in terms of the fact that the difference in permittivity between two layers is substantially limited because high-k polymer materials are insufficient.